The relation between quantity of Mentos and height of Diet Coke rocket.
Robbie, Jack, Cameron
Introduction
The urban legend of the explosive reaction from mint Mentos and diet coke has been played with among experiments for a little more than a decade now. Since around 1999, when the experiment was first conducted by school teacher Lee Marek, the reaction has made for a popular YouTube video. The powerful geyser reaction was popular, but no one knew why it happened. That is until scientists looked into it deeper in 2008. They discovered that the rough, dimply surfaces of Mentos produce bubble growth because they disrupt the polar attractions between water molecules, creating bubble growth sites and there for more pressure3. Once the top is broken from the bottle the build up of CO2 shoots the diet coke from the bottle and when upside down gives it force to lift off. One way the experiment has been executed is to launch the diet coke and mentos as a rocket, and that’s what we worked with. We wanted to see if the amount of mentos in a consistent sized diet coke bottle would increase the height of the rocket or stay the same.
Procedure
We started off our experiment by using a 4 foot tall by 3 inches wide piece of CPVC, 20 (12 fluid ounces) diet cokes, and 45 Mentos. We used a meter stick and the program Logger-Pro to measure the height of the rocket. Our plan was to do 4 trials with 2 Mentos, 4 trials with 4 Mentos, 4 trials with 5 Mentos, and 4 trials with 6 Mentos. We used a piece of tape to hold the Mentos together as we lowered them into the Diet Coke. We let the pressure build up, by shaking it up, inside the bottle then sent it through the tube. Our hope was the the force of the bottle falling would break the cap and send the bottle shooting through the tube and into the sky. Unfortunately the force was not strong enough the break the bottle so we decided to move to a different way of breaking the bottle. Our other way was dropping it off an elevated platform. We used the same way of measuring. This way proved to be quite successful. We kept the height consistent but changed the number of Mentos added to the Diet Coke.
Results
Trial 1
Mentos
2
4
5
6
Height (meters)
.23
.78
1.34
1.2
Trial 2
Mentos
2
4
5
6
Height (meters)
.56
.9
1.5
2
Trial 3
Mentos
2
4
5
6
Height (meters)
.5
.8
1.2
2.4
Trial 4
Mentos
2
4
5
6
Height (meters)
.3
.87
1.45
2.1
P=.007
We used a T-test to get to this result.
Conclusions
We concluded that our hypothesis was true. With the number of Mentos added to the diet coke the height of the rocket also increased. We also concluded that the force needed to break a Diet Coke bottle is much stronger than we first believed. If you are trying to repeat this experiment we suggest that you should use a full 2 liter bottle for the experiment because there is more liquid to react. We also suggest that you avoid using a PVC pipe for any type of homemade rocket, because it makes it difficult to launch.Another idea for future experiments would be to try different sodas. For example diet pepsi vs diet coke, regular coke vs diet coke, etc.
Table of Contents
The relation between quantity of Mentos and height of Diet Coke rocket.
Robbie, Jack, Cameron
Introduction
The urban legend of the explosive reaction from mint Mentos and diet coke has been played with among experiments for a little more than a decade now. Since around 1999, when the experiment was first conducted by school teacher Lee Marek, the reaction has made for a popular YouTube video. The powerful geyser reaction was popular, but no one knew why it happened. That is until scientists looked into it deeper in 2008. They discovered that the rough, dimply surfaces of Mentos produce bubble growth because they disrupt the polar attractions between water molecules, creating bubble growth sites and there for more pressure3. Once the top is broken from the bottle the build up of CO2 shoots the diet coke from the bottle and when upside down gives it force to lift off. One way the experiment has been executed is to launch the diet coke and mentos as a rocket, and that’s what we worked with. We wanted to see if the amount of mentos in a consistent sized diet coke bottle would increase the height of the rocket or stay the same.Procedure
We started off our experiment by using a 4 foot tall by 3 inches wide piece of CPVC, 20 (12 fluid ounces) diet cokes, and 45 Mentos. We used a meter stick and the program Logger-Pro to measure the height of the rocket. Our plan was to do 4 trials with 2 Mentos, 4 trials with 4 Mentos, 4 trials with 5 Mentos, and 4 trials with 6 Mentos. We used a piece of tape to hold the Mentos together as we lowered them into the Diet Coke. We let the pressure build up, by shaking it up, inside the bottle then sent it through the tube. Our hope was the the force of the bottle falling would break the cap and send the bottle shooting through the tube and into the sky. Unfortunately the force was not strong enough the break the bottle so we decided to move to a different way of breaking the bottle. Our other way was dropping it off an elevated platform. We used the same way of measuring. This way proved to be quite successful. We kept the height consistent but changed the number of Mentos added to the Diet Coke.
Results
Trial 1We used a T-test to get to this result.
Conclusions
We concluded that our hypothesis was true. With the number of Mentos added to the diet coke the height of the rocket also increased. We also concluded that the force needed to break a Diet Coke bottle is much stronger than we first believed. If you are trying to repeat this experiment we suggest that you should use a full 2 liter bottle for the experiment because there is more liquid to react. We also suggest that you avoid using a PVC pipe for any type of homemade rocket, because it makes it difficult to launch.Another idea for future experiments would be to try different sodas. For example diet pepsi vs diet coke, regular coke vs diet coke, etc.References
1. http://thetartan.org/2007/2/19/scitech/how
2. http://pisci.wikispaces.com/Alka-Seltzer+and+Coke
3. http://www.newscientist.com/article/dn14114-science-of-mentosdiet-coke-explosions-explained.html